The present invention relates to an apparatus for preventing air from entering into the operative portion of an artificial organ such as an artificial kidney, a dialyzer, a hemofilter, or an artificial liver, for example including a hemoperfusion cartridge.
During a dialysis treatment, air frequently enters the dialyzer space containing the dialysate because in the most frequent type of operation a reduced pressure is present in the space containing the dialysate. As a result, air may be drawn into such space through possible leaks or because the dialysate solution has not been degassed sufficiently.
Thus, if air enters into the dialysate containing space of the dialyzer larger air bubbles are often produced which can be removed only very slowly by dissolving the air into the degassed dialysate. Such air bubbles cover the operative surface portions of the artificial organ membrane. The efficiency of the diffusion exchange between the blood flowing on one side of the membrane and the dialysate flowing on the other side of the membrane is correspondingly impaired or diminished by such air bubbles.
Similar considerations apply when air enters into the space of the dialyzer on the side through which the blood flows similarly covering respective membrane surface areas. Another disadvantage is that air on the blood flow side increases the danger of clotting. An air bubble in the blood flow channel, for example, between the supporting grids or in a hollow fiber reduces the flow speed of the blood.
Similar difficulties may occur in a hemofilter where no dialysate is used. Rather, a fraction of the blood is caused to pass under pressure through the hemofilter membrane for separating a blood fraction by filtration.